v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 01, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Information [Line Items]    
Entity Registrant Name ISQ Open Infrastructure Company LLC  
Entity Central Index Key 0002059924  
Entity File Number 000-56735  
Entity Tax Identification Number 33-2876284  
Entity Incorporation, State or Country Code DE  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Contact Personnel [Line Items]    
Entity Address, Address Line One 600 Brickell Avenue  
Entity Address, City or Town Miami  
Entity Address, State or Province FL  
Entity Address, Postal Zip Code 33131  
Entity Phone Fax Numbers [Line Items]    
City Area Code (786)  
Local Phone Number 693-5700  
Entity Listings [Line Items]    
Title of 12(b) Security None  
No Trading Symbol Flag true  
ISQ Open Infrastructure Company LLC - Series II | Class F-STE    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   1,295,412
ISQ Open Infrastructure Company LLC - Series II | Class STE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   110
ISQ Open Infrastructure Company LLC - Series II | Class DTE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   110
ISQ Open Infrastructure Company LLC - Series II | Class JTE    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   112,047
ISQ Open Infrastructure Company LLC - Series II | Class ETE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   81
ISQ Open Infrastructure Company LLC - Series II | Class F-I shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   863,457
ISQ Open Infrastructure Company LLC - Series II | Class F-J Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   4,251,130
ISQ Open Infrastructure Company LLC - Series I | Class F-STE    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   2,331,292
ISQ Open Infrastructure Company LLC - Series I | Class F-DTE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   405,809
ISQ Open Infrastructure Company LLC - Series I | Class F-STE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   164,393
ISQ Open Infrastructure Company LLC - Series I | Class F-JTE Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   749,143
ISQ Open Infrastructure Company LLC - Series I | Class I Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   16,242
ISQ Open Infrastructure Company LLC - Series I | Class J Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   284,384
ISQ Open Infrastructure Company LLC - Series I | Class E Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   469,016
ISQ Open Infrastructure Company LLC - Series I | Class ITE    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   110